Artificial chiral systems can perform fascinating tasks like chiral sensing, chiral catalysis, chiral separation, chiral optoelectronics and so forth. In these applications, enantiodifferentiation is a key and fundamental role. Since the enantiodifferentiation relies on certain stereoselective interactions between the chiral materials and the stereoisomers introduced, current artificial chiral systems are normally enantioselective only for one or a few of chiral isomers. To sense the single enantiomer of a diverse series of chiral species via a single-material design is tremendously challenging, simply because the stereoselective interactions among a large number of chiral substrates behaves to different degrees. Although it is common to tell any of the enantiomers by monitoring their optical activity with physical devices, it would be desirable and valuable to achieve a general enantiodifferentiation by a portable chemical strategy.

   Therefore, Zhu’s group planed to design a high sensitive material with significantly amplified stereoselective interactions to address the above-mentioned challenge. In this work, they chose organogel as the chemical platform since the gel-to-micelle transformation (gel collapse) upon enantiorecognition can be easily visualized. To sufficiently amplify the stereoselective interactions of an organogel, they developed a paradigm of creating a hierarchically co-assembled organogel to overcome the dilemma. Their system is composed of a chiral rigid molecular linker and an achiral block copolymer (BCP) through H-bonding, enabling that the chirality transfer from the linker to the BCP directed the co-assembly to form a phase-segregated twisted nanofiber. In this way, the rigid chiral linker can serve as the scaffold in the crosslinked nanofibers of the gel, making the material highly sensitive and the stereoselective interactions amplified possible. On this basis, their system can enable a naked-eye sensing towards the single enantiomer of a diverse series of chiral species (including axial, point, planar, and polymeric chirality) via gel-to-micelle transformation, rather than their enantio-counterpart.
       

    This work could pave a way to greatly facilitate an easy-to-handle identification of a broad enantiomers by visualization independent of opticity measurement by devices. The related paper has been published in ACS Nano (DOI: 10.1021/acsnano.9b06250), with Dr. Bingbing Yue, a former PhD student in the group (now graduate for Lecturer at USST) as the first author. See details: https://pubs.acs.org/doi/full/10.1021/acsnano.9b06250.